Elastic blends comprising crystalline polymer and crystallizabe polymers of propylene

ABSTRACT

Improved thermoplastic polymer blend compositions comprising an isotactic polypropylene component and an alpha-olefin and propylene copolymer component, said copolymer comprising crystallizable alpha-olefin sequences. In a preferred embodiment, improved thermoplastic polymer blends are provided comprising from about 35% to about 85% isotactic polypropylene and from about 30% to about 70% of an ethylene and propylene copolymer, wherein said copolymer comprises isotactically crystallizable propylene sequences and is predominately propylene. The resultant blends manifest unexpected compatibility characteristics, increased tensile strength, and improved process characteristics, e.g., a single melting point.

FIELD OF THE INVENTION

The invention relates to a blend of at least two thermoplasticcomponents differing in their crystallinities. The blend has aheterogeneous morphology with distinct phase separated zones ofdifferent composition and crystallinity present. The resulting blendwith the defined morphology shows dramatic improvements in mechanicaldeformation recoverability when compared to its individual unblendedcomponents. The invention also relates to improvements in theflexibility of the blend. Changes in the relative amounts or thecrystallinities of the blend components or the morphology of the blendaffect the recoverability and the flexibility of the blend.

The inventive blends designed for recoverability contains a dispersedphase of a greater crystallinity and a continuous phase of lessercrystallinity. The sizes of the individual domains of the dispersedphase are very small with the smallest length dimension for thedispersed phase being less than 5 μm. This phase size of the dispersedphase is maintained during processing even without crosslinking. Theinventive blends designed for flexibility have a slightly wider range inmorphology as the components of greater and lesser crystallinity canalso be co-continuous. The components of the blend in both cases arealso compatible to the extent that no compatibilizer needs to be addedto attain and retain this fine morphology. Furthermore, this inventiondescribes improving the mechanical deformation recoverability of theaforementioned blends by aging the blends and mechanically orienting thearticles formed from these blends.

One of the components is a polymer comprising predominatelystereospecific polypropylene, preferably isotactic polypropylene. Thisis the component with greater crystallinity. A second component is acopolymer of propylene and a C₂, C₃-C₂₀ α-olefin, preferably ethylene.This is the component with lesser crystallinity. In the copolymer thepropylene is polymerized substantially stereospecifically. The copolymerhas a substantially uniform composition distribution preferably as aresult of polymerization with a metallocene catalyst. Most preferably,said second component is an ethylene propylene copolymer, e.g. ethylenepropylene semicrystalline elastomer.

BACKGROUND OF THE INVENTION

There is a need in the art for polymeric blends having a stereospecificpolypropylene component with good tensile strength while still providingsuitable mechanical recoverability (elastic recovery) and flexibility(low flexural modulus). This invention is aimed at improving theaforementioned properties of blends having a stereoregular polypropylenecomponent, especially isotactic polypropylene. This is achieved byblending the stereoregular polypropylene component with a copolymer ofpropylene and a C₂, C₃-C₂₀ α-olefin. This copolymer is less crystallinethan the isotactic polypropylene. In the copolymer the propylene ispolymerized substantially stereospecifically. Most preferably, thecopolymer is an ethylene propylene copolymer, e.g., ethylene propylenethermoplastic elastomer. The copolymer has a substantially uniformcomposition distribution preferably as a result of polymerization with ametallocene catalyst Composition distribution is a property ofcopolymers indicating a statistically significant intermolecular orintramolecular difference in the composition of the polymer. Methods formeasuring compositional distribution are described later.

Blends of isotactic polypropylene and ethylene propylene rubber are wellknown in the prior art. However, the traditional Ziegler-Natta catalystscannot make ethylene propylene thermoplastic elastomers whichsimultaneously are uniform in compositional distribution, havesubstantially stereospecific propylene residues and have less than 35wt. % ethylene.

U.S. Pat. No. 3,882,197 to Fritz et al. describes blends ofstereoregular propylene/alpha-olefin copolymers, stereoregularpropylene, and ethylene copolymer rubbers. In U.S. Pat. No. 3,888,949Chi-Kai Shih, assigned to E I Du Pont, shows the synthesis of blendcompositions containing isotactic polypropylene and copolymers ofpropylene and an alpha-olefin, containing between 6-20 carbon atoms,which have improved elongation and tensile strength over either thecopolymer or isotactic polypropylene. Copolymers of propylene andalpha-olefin are described wherein the alpha-olefin is hexene, octene ordodecene. However, the copolymer is made with a heterogeneous titaniumcatalyst resulting in copolymers with non-uniform compositiondistribution and a broad molecular weight distribution. Non-uniformintramolecular compositional distribution is evident in U.S. Pat. No.3,888,949 by the use of the term “block” in the description of thepolymer where the copolymer is described as having “sequences ofdifferent alpha-olefin content.” Within the context of the inventiondescribed above the term sequences describes a number of olefin monomerresidues linked together by chemical formed during polymerization.

In U.S. Pat. No. 4,461,872, A. C. L. Su improved on the properties ofthe blends described in U.S. Pat. No. 3,888,949 by using anotherheterogeneous catalyst system which is expected to form copolymers whichhave statistically significant intermolecular and intramolecularcompositional differences.

In two successive publications in the journal of Macromolecules, 1989,V22, pages 3851-3866, J. W. Collette of E. I. Du Pont has describedblends of isotactic polypropylene and partially atactic polypropylenewhich have desirable tensile elongation properties. However, thepartially atactic propylene has a broad molecular weight distribution asshown in FIG. 8 of the first publication. The partially atacticpolypropylene is also composed of several fractions, which differ in thelevel of tacticity of the propylene units as shown by the differences inthe solubility in different solvents. This is shown by the correspondingphysical decomposition of the blend which is separated by extractionwith different solvents to yield individual components of uniformsolubility characteristics as shown in Table IV of the abovepublications.

More recently several authors have shown the formation of more refinedstructures of partially atactic, partially isotactic polypropylene whichhave elastomeric properties. It is believed that in these componentseach molecule consists of portions which are isotactic and thereforecrystallizable while the other portions of the same polypropylenemolecule are atactic and therefore amorphous. Examples of thesepropylene homopolymers containing different levels of isotacticity indifferent portions of the molecule are described by R. Waymouth in U.S.Pat. No. 5,594,080, in the article in the Journal American ChemicalSociety (1995), Vol. 117, page 11586, and in the article in the JournalAmerican Chemical Society (1997), Vol. 119, page 3635, J. Chien in thejournal article in the Journal of the American Chemical Society (1991),Vol. 113, pages 8569-8570; and S. Collins in the journal article inMacromolecules (1995) Vol. 28, pages 3771-3778. These articles describea specific polymer, but do not describe the blends with a morecrystalline polymer such as isotactic polypropylene.

In U.S. Pat. Nos. 3,853,969 and 3,378,606, E. G. Kontos discloses theformation of in situ blends of isotactic polypropylene and “stereoblock” copolymers of propylene and another olefin of 2 to 12 carbonatoms, including ethylene and hexene. The copolymers of this inventionare necessarily heterogeneous in intermolecular and intramolecularcomposition distribution. This is demonstrated by the synthesisprocedures of these copolymers which involve sequential injection ofmonomer mixtures of different compositions to synthesize polymericportions of analogously different compositions. In addition, FIG. 1 ofboth patents shows that the “stereo block” character, which is intra orintermolecular compositional differences in the context of thedescription of the present invention, is essential to the benefit of thetensile and elongation properties of the blend. Moreover, all of thesecompositions either do not meet all of the desired properties forvarious applications, and/or involve costly and burdensome process stepsto achieve the desired results.

Similar results are anticipated by R. Holzer and K. Mehnert in U.S. Pat.No. 3,262,992 assigned to Hercules wherein the authors disclose that theaddition of a stereoblock copolymer of ethylene and propylene toisotactic polypropylene leads to improved mechanical properties of theblend compared to isotactic polypropylene alone. However, these benefitsare described only for the stereoblock copolymers of ethylene andpropylene. These copolymers were synthesized by changing the monomerconcentrations in the reactor with time. This is shown in examples 1 and2. The stereoblock character of the polymer is graphically shown in themolecular description (column 2, line 65) and contrasted with theundesirable random copolymer (column 2, line 60). The presence ofstereoblock character in these polymers is shown by the high meltingpoint of these polymers and the poor solubility in hydrocarbons atambient temperature.

There is a need for a polyolefin blend composition which is thermallystable, heat resistant, light resistant and generally suitable forthermoplastic elastomer (TPE) applications which has advantageousprocessing characteristics. We have found that by blending a crystallinepropylene polymer, hereinafter referred to as the “first polymercomponent, (FPC)” and a crystallizable propylene alpha olefin copolymerpolymer, hereinafter referred to as the “second polymer component(SPC)”, advantageous processing characteristics result while stillproviding a composition having decreased flexural modulus and increasedtensile strength, elongation, recovery and overall toughness. It ispossible to have the addition of a third polymeric component which isanother crystallizable propylene alpha olefin copolymer indicated asSPC2 in the text below which has crystallinity intermediate between theFPC and the SPC. The SPC2 also has a narrow composition distribution andis made with a metallocene catalyst. The addition of SPC2 leads to afiner morphology and improvements in some of the properties of the blendof FPC and SPC.

The term “crystalline,” as used herein for FPC, characterizes thosepolymers which possess high degrees of inter- and intra-molecular order,and which melt higher than 110° C. and preferably higher than 115° C.and more preferably higher than 130° C. and preferably have a heat offusion of at least 75 J/g, as determined by DSC analysis. And, the term“crystallizable,” as used herein for SPC describes polymers which aremainly amorphous in the undeformed state, but can crystalize uponstretching or annealing. Crystallization may also be initiated by thepresence of a crystalline polymer such as the FPC. These polymers have amelting point of less than 105° C. or preferably less than 100° C. andpreferably have a heat of fusion of less than 75 J/g as determined byDSC. SPC2 describes those polymers that are substantially crystalline inthe undeformed state. Further crystallization may also occur in thepresence of the crystalline polymer such as FPC. These polymers have amelting point of less than 115° C. or preferably less than 100° C. andpreferably have a heat of fusion of less than 75 J/g as determined byDSC.

SUMMARY OF THE INVENTION

The present invention is directed to blends with heterophase morphologyformed by blending a FPC which is a predominately crystallinestereoregular polypropylene with a SPC which is a crystallizablecopolymer of a C₂, C₄-C₂₀ α-olefin (preferably ethylene) and propylene.Optional components of the blend are SPC2, a crystallizable copolymer ofa C₂, C₄-C₂₀ α-olefin (preferably ethylene), and process oil. Otheroptional components are fillers, colorants, antioxidants, nucleators andflow improvers.

The FPC melts higher than 110° C. and preferably higher than 115° C. andmore preferably higher than 130° C. and preferably has a heat of fusionof at least 75 J/g, as determined by DSC analysis. The crystallinepolypropylene can be either homopolymer or copolymers with other alphaolefins. The FPC may also be comprised of commonly available isotacticpolypropylene compositions referred to as impact copolymer or reactorcopolymer. However these variations in the identity of the FPC areacceptable in the blend only to the extent that the FPC is within thelimitations of the crystallinity and melting point indicated above. TheFPC may also contain additives such as flow improvers, nucleators andantioxidants which are normally added to isotactic polypropylene toimprove or retain properties. All of these polymers are referred to asthe FPC.

The SPC and the SPC2, if used, have stereoregular propylene sequenceslong enough to crystallize. The SPC has a melting point of less than105° C. or preferably less than 100° C. and preferably has a heat offusion of less than 75 J/g. The SPC2 has a melting point of less than115° C. or preferably less than 100° C. and preferably has a heat offusion of less than 75 J/g. These stereoregular propylene sequences ofSPC and SPC2 should substantially match the stereoregularity of thepropylene in the first polymer. For example, if the FPC is predominatelyisotactic polypropylene, then the SPC, and SPC2 if used, is copolymerhaving isotactic propylene sequences. If the FPC is predominatelysyndiotactic polypropylene, then the SPC, and the SPC2 if used, is acopolymer having syndiotactic sequences. Therefore, SPC and SPC2 havesimilar, preferably substantially identical, tacticity to the FPC. It isbelieved that this matching of stereoregularity increases thecompatibility of the components and results in improved adhesion at theinterface of the domains of the polymers of different crystallinities inthe polymer blend composition. Furthermore, good compatibility is onlyachieved in a narrow range of copolymer composition for the SPC. Narrowintermolecular and intramolecular compositional distribution in thecopolymer is preferred. The aforementioned characteristics of the SPC,and SPC2 if used, are preferably achieved by polymerization with achiral metallocene catalyst.

One preferable embodiment is blending isotactic polypropylene (FPC) withethylene propylene copolymers (SPC) having about 4 wt. % to about 35 wt.% ethylene (to ensure high compatibility with the FPC). Both the FPC andthe SPC have isotactic propylene sequences long enough to crystallize.Resulting blends of isotactic polypropylene with ethylene propylenecopolymers according to the invention have improved properties ascompared to isotactic polypropylene blends with prior art ethylenepropylene rubbers.

A preferred blend comprises 1% to 95% by weight of FPC and a SPC withgreater than 65% by weight propylene and preferably greater than 80% byweight propylene.

According to another embodiment, a thermoplastic polymer blendcomposition of the invention comprises a FPC and a SPC with addedprocess oil. The FPC comprises isotactic polypropylene, a reactorcopolymer or an impact copolymer as described above and is present in anamount of about 1% to about 95% by weight and more preferably 2% to 70%by weight of the total weight of the blend. The balance of the polymercomposition consists of a mixture of the process oil and the SPC andSPC2 if used.

The SPC is a random copolymer of ethylene and propylene having a meltingpoint by DSC of 0° C. to 105° C., preferably in the range 20° C. to 90°C., more preferably in the range of 25° C. to 70° C. and an averagepropylene content by weight of at least 65% and more preferably at least80% This melting point is due to crystallizable propylene sequences,preferrably of isotactic polypropylene. The SPC is made with apolymerization catalyst which forms essentially or substantiallyisotactic polypropylene, when all or substantially all propylenesequences in the FPC are isotactic. The SPC is statistically random inthe distribution of the ethylene and propylene residues along the chain.Quantitative evaluation of the randomness of the distribution of theethylene and propylene sequences may be obtained by consideration of theexperimentally determined reactivity ratios of the second polymercomponent or by 13 C NMR. This is according to the procedures describedin the journal article by H. Kakugo, Y Naito, K. Mizunama and T.Miyatake in Macromolecules (1982), pages 1150-1152. The SPC is made witha single sited metallocene catalyst which allows only a singlestatistical mode of addition of ethylene and propylene by polymerizationin a well mixed, continuous feed stirred tank reactor which provides auniform polymerization environment for growth of all of the polymerchains of the SPC.

The ratio of the FPC to the SPC of the blend composition of the presentinvention may vary in the range of 1:99 to 95:5 by weight and morepreferably in the range 2:98 to 70:30 by weight.

According to another embodiment of the present invention, the secondpolymer component may contain small quantities of a non-conjugated dieneto aid in the vulcanization and other chemical modification of the blendof the first polymer component and the second polymer component. Theamount of diene is preferably less than 10 wt. % and preferably lessthan 5 wt. %. The diene may be selected from the group consisting ofthose which are used for the vulcanization of ethylene propylene rubbersand are preferably ethylidene norbornene, vinyl norbornene anddicyclopentadiene.

The SPC2, if used, has the same characteristics as the SPC describedabove. The SPC2 has a crystallinity and composition intermediate betweenthe FPC and the SPC. In the preferred case where the SPC2 is a copolymerof ethylene and propylene while the FPC is homopolymer of propylene. TheSPC2 has the same type of crystallinity of propylene as in the FPC andSPC and an ethylene content in between FPC and SPC. The addition of SPC2to the blend leads to a better dispersion of the phases in the blendcompared to blends of the similar composition which do not have anySPC2. The relative amounts of SPC and SPC2 can vary between 95:5 to10:90 in the blend. The ratio of the FPC to the sum of SPC and SPC2 mayvary in the range of 1:99 to 95:5 by weight and more preferably in therange 2:98 to 70:30 by weight.

According to still a further embodiment, the invention is directed to aprocess for preparing thermoplastic polymer blend compositions. Theprocess comprises: (a) polymerizing propylene or a mixture of propyleneand one or more monomers selected from C₂ or C₃-C₂₀ α-olefins in thepresence of a polymerization catalyst wherein a substantially isotacticpropylene polymer containing at least about 90% by weight polymerizedpropylene is obtained; (b) polymerizing a mixture of ethylene andpropylene in the presence of a chiral metallocene catalyst, wherein acopolymer of ethylene and propylene is obtained comprising up to about35% by weight ethylene and preferably up to 20% by weight ethylene andcontaining isotactically crystallizable propylene sequences; and (c)blending the propylene polymer of step (a) with the copolymer of step(b) to form a blend.

The invention is directed to the formation of a blend of the componentsFPC, SPC and SPC2 which has a heterogeneous phase morphology consistingof domains of different crystallinities. Blends directed to improvementin the elastic recovery have a continuous phase of lower crystallinityand a dispersed phase of the higher crystallinity. The domains of thedispersed phase are small with an average minimum axis less than 5 μm.The larger axis of the dispersed phase can be as large as 100 μm. Thedispersed phase consists of a crystalline mixture of FPC with someamount of SPC2 and SPC due to thermodynamic mixing of polymers. Thecontinuous phase consists of the balance of the polymers not included inthe dispersed phase. Blends directed to low flexural modulus may have inaddition, a heterogeneous phase morphology with continuous phases oflower and greater crystallinity.

Commonly available propylene reactor copolymers consisting of a singlephase blend of isotactic polypropylene and copolymers of propylene andethylene are not included within the scope of the invention since theyare a single phase with no prominent dispersed or continuous phases.Polypropylene blends made by a combination of a FPC and a SPC of thepresent invention that give a heterophase morphology in which thecrystalline polymer is the continuous phase in are excluded from theinvention.

The benefits of the invention are included improvement in the elasticrecovery and the flexural modulus of the blend. These improvements aremost apparent as a function of the 500% tensile modulus of the blend.Historically, the examples of the prior art have been able to duplicatethe improvements in the blend but only for compositions with a very low500% tensile modulus

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the morphology of a blend of this invention. Specifically,FIG. 1 shows the morphology of sample H7 in Example 6 below.

FIG. 2 shows the morphology of a blend of this invention. Specifically,FIG. 2 shows the morphology of sample K7 in Example 6 below.

FIG. 3 shows the morphology of a blend of this invention which includesSPC2. Specifically, FIG. 3 shows the morphology of sample BB7 in Example6 below.

FIG. 4 and FIG. 5 show the stress strain elongation data for blends ofthis invention.

FIG. 6 shows the elastic recovery of annealed/aged blends of thisinvention.

FIG. 7 shows the elastic recovery of oriented blends of this invention.

FIG. 8 shows the dependence of the flexural modulus of the blend of thisinvention as a correlated function of the 500% tensile modulus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The blend compositions of the present invention generally are comprisedof two components: (1) a crystalline FPC comprising isotacticpolypropylene and (2) a crystallizable SPC comprising an alpha-olefin(other than propylene) and propylene copolymer. A particular embodimentof the invention contains a crystallizable SPC2 comprising analpha-olefin (other than propylene) and propylene copolymer. Aparticular embodiment of the invention may comprise process oil as anadditional component.

The blend also has a heterogeneous phase morphology where a morecrystalline polymer mixture consisting essentially of all the FPC andsome of the SPC and SPC2 is dispersed in domains in a continuous phaseof a less crystalline polymer mixture containing the balance of theblend. The size of the dispersed domains is small and the morphology isstable in the absence of a compatibilizer. Prefereably, compositions ofthe invention are free of, or substantially free of, compatibilizers.

The First Polymer Component (FPC)

In accordance with the present invention, the FPC component i.e., thepolypropylene polymer component may be homopolypropylene, or copolymersof propylene, or some mixtures thereof. The FPC has the followingcharacteristics.

(A) The polypropylene of the present invention is predominatelycrystalline, i.e., it has a melting point generally greater than about110° C., preferably greater than about 115° C., and most preferablygreater than about 130° C. Preferably, it has a heat of fusion greaterthan 75 J/g.

(B) The polypropylene can vary widely in composition. For example,substantially isotactic polypropylene homopolymer or propylene copolymercontaining equal to or less than about 10 weight percent of othermonomer, i.e., at least about 90% by weight propylene can be used.Further, the polypropylene can be present in the form of a graft orblock copolymer, in which the blocks of polypropylene have substantiallythe same stereoregularity as the propylene-alpha-olefin copolymer, solong as the graft or block copolymer has a sharp melting point aboveabout 110° C., preferably above 115° C., and more preferably above 130°C., characteristic of the stereoregular propylene sequences. Thepropylene polymer component may be a combination of homopolypropylene,and/or random, and/or block copolymers as described herein. When theabove propylene polymer component is a random copolymer, the percentageof the copolymerized alpha-olefin in the copolymer is, in general, up toabout 9% by weight, preferably about 2% to about 8% by weight, mostpreferably about 2% to about 6% by weight. The preferred alpha-olefinscontain 2 or from 4 to about 12 carbon atoms. The most preferredalpha-olefin is ethylene. One or two or more alpha-olefins can becopolymerized with propylene.

Exemplary alpha-olefins may be selected from the group consisting ofethylene; butene-1; pentene-1,2-methylpentene-1,3-methylbutene-1;hexene-1,3 -methylpentene-1,4-methylpentene-1,3,3-dimethylbutene-1;heptene-1; hexene-1; methylhexene-1; dimethylpentene-1trimethylbutene-1; ethylpentene-1; octene-1; methylpentene-1;dimethylhexene-1; trimethylpentene-1; ethylhexene-1;methylethylpentene-1; diethylbutene-1; pyopylpentane-1; decene-1;methylnonene-1; nonene-1; dimethyloctene-1; trimethylheptene-1;ethyloctene-1; methylethylbutene-1; diethylhexene-1; dodecene-1 andhexadodecene-1.

(C) The molecular weight of the FPC can be between 10,000 to 5,000.000with a polydispersity index (PDI) between 1.5 to 40.0.

(D) The thermoplastic polymer blend compositions of the presentinvention may comprise from about 1% to about 95% by weight of FPC.According to a preferred embodiment, the thermoplastic polymer blendcomposition of the present invention may comprise from about 2% to about70% by weight of the FPC. According to the most preferred embodiment,the compositions of the present invention may comprise from about 2% toabout 40% by weight of the FPC. An even more preferred embodiment of theinvention contains 2% to 25% by weight of FPC in the blend.

There is no particular limitation on the method for preparing thispropylene polymer component of the invention. However, in general, thepolymer is a propylene homopolymer obtained by homopolymerization ofpropylene in a single stage or multiple stage reactor. Copolymers may beobtained by copolymerizing propylene and an alpha-olefin having 2 orfrom 4 to about 20 carbon atoms, preferably ethylene, in a single stageor multiple stage reactor. Polymerization methods include high pressure,slurry, gas, bulk, or solution phase, or a combination thereof, using atraditional Ziegler-Natta catalyst or a single-site, metallocenecatalyst system. The catalyst used is preferably one which has a highisospecificity. Polymerization may be carried out by a continuous orbatch process and may include use of chain transfer agents, scavengers,or other such additives as deemed applicable.

The Second Polymer Component (SPC)

The SPC of the polymer blend compositions of the present inventioncomprises a crystallizable copolymer of propylene and anotheralpha-olefin having less than 10 carbon atoms, preferably ethylene. TheSPC has the following characteristics:

(A) The SPC of the present invention preferably comprises a randomcopolymer having a narrow compositional distribution. While not meant tobe limited thereby, it is believed that the narrow compositiondistribution of the second polymer component is important. Theintermolecular composition distribution of the polymer is determined bythermal fractionation in a solvent. A typical solvent is a saturatedhydrocarbon such as hexane or heptane. This thermal fractionationprocedure is described below. Typically, approximately 75% by weight andmore preferably 85% by weight of the polymer is soluble in one or twoadjacent fractions with the balance of the polymer in immediatelypreceding or succeeding fractions. Each of these fractions-has acomposition (wt. % ethylene content) with a difference of no greaterthan 20 wt. % (relative) and more preferably 10 wt. % (relative) of theaverage wt. % ethylene content of the whole second polymer component.The second polymer component is narrow in compositional distribution ifit meets the fractionation test outlined above.

(B) In all SPC, the length and distribution of stereoregular propylenesequences is consistent with the substantially random statisticalcopolymerization. It is well known that sequence length and distributionare related to the copolymerization reactivity ratios. By substantiallyrandom, we mean copolymer for which the product of the reactivity ratiosis 2 or less. In stereoblock structures, the average length of PPsequences is greater than that of substantially random copolymers with asimilar composition. Prior art polymers with stereoblock structure havea distribution of PP sequences consistent with these blocky structuresrather than a random substantially statistical distribution. Thereactivity ratios and sequence distribution of the polymer may bedetermined by C-13 NMR which locates the ethylene residues in relationto the neighboring propylene residues. To produce a copolymer with therequired randomness and narrow composition distribution, it is desirableto use (I) a single sited catalyst and (2) a well-mixed, continuous flowstirred tank polymerization reactor which allows only a uniformpolymerization environment for growth of substantially all of thepolymer chains of the second polymer component.

(C) The SPC preferably has a single melting point. The melting point isdetermined by DSC. Generally, the SPC of the present invention has amelting point between about 105° C. and 0° C. Preferably, the meltingpoint of SPC is between about 90° C. and 20° C. Most preferably,according to one embodiment of the present invention, the melting pointof the SPC of the composition of the present invention is between 70° C.and 25° C.

(D) The second polymer component of the present inventive compositioncomprises crystallizable propylene sequences. The crystallinity of thesecond polymer component is, preferably, according to one embodiment,from about 1% to about 65% of homoisotactic polypropylene, preferablybetween 3% to 30%, as measured by the heat of fusion of annealed samplesof the polymer.

(E) The molecular weight of the SPC can be between 10,000 to 5,000,000with a polydispersity index (PDI) between 1.5 to 40.0. The secondpolymer component preferably has a narrow PDI between about 1.8 to about5. It is preferred if the SPC has a Mooney Viscosity at 125° C. lessthan 100, more preferably less than 75 and more preferably less than 60.

(F) The low levels of crystallinity in the SPC are obtained byincorporating from about 5% to about 35% by weight alpha-olefin,preferably from about 6% to about 30% by weight alpha-olefin, and mostpreferably, it comprises from about 8% to about 25% by weightalpha-olefin and even more preferably between 8% to 20% by alpha-olefin.These composition ranges for the SPC are preferred to obtain theobjectives of the present invention. Alpha olefins comprise one or moremembers of the group C₂, C₄-C₂₀ α-olefin. At alpha-olefin compositionslower than the above lower limits for the composition of the SPC, theblends of the FPC and SPC are thermoplastic and do not have the phaseseparated morphology required for the tensile recovery properties of theblends. At alpha-olefin compositions higher than the above higher limitsfor the SPC, the blends have poor tensile strength and a phase separatedmorphology with a coarse dispersion. It is believed, while not meant tobe limited thereby, the SPC needs to have the optimum amount ofpolypropylene crystallinity to crystallize with the FPC for thebeneficial effects of the present invention. As discussed above, thepreferred alpha-olefin is ethylene.

(G) The compositions of the present invention may comprise from about 5%to about 99% by weight of the SPC and from about 30% to about 98% byweight of the SPC. Most preferably, they comprise from about 60% toabout 98% and even more preferably 75% to 99% by weight of the SPC.

(H) More than one SPC may be used in a single blend with a FPC. Each ofthe SPC is described above and the number of SPC in this embodiment isless than three and more preferably, two. The different SPC differ inthe crystallinity. For two SPC components, the SPC2 is more crystallinethan the SPC. The SPC2 has, preferably, according to one embodiment,from about 20% to about 65%, and more preferably between 25% to 65% ofthe crystallinity of homoisotactic polypropylene as measured by the heatof fusion of annealed samples of the polymer. The SPC and the SPC2 mayalso differ in their molecular weight. The SPC and SPC2 differ in thealpha-olefin content consistent with the use of two SPC with differentcrystallinity. The preferred alpha-olefin is ethylene. It is believedthat the use of SPC2 in conjunction with a blend of a FPC and a SPC actsas an interfacial agent in these blends. The resultant morphologyconsists of a finer dispersion of the highly crystalline component withthe continuous phase of the less crystalline phase. Such a morphologyleads to in the elastic recovery properties of the blends.

The second polymer component may also comprise a copolymer of atacticpropylene and isotactic propylene. Such crystallizable homopolymers ofpropylene have been described by R. Waymouth in U.S. Pat. No. 5,594,080,which is included herein by reference. Optionally, the second componentof the composition of the present invention may comprise a diene.

(I) The SPC and the SPC2, if used, have stereoregular propylenesequences long enough to crystallize. These stereoregular propylenesequences of SPC and SPC2 should match the stereoregularity of thepropylene in the second polymer. For example, if the FPC ispredominately isotactic polypropylene, then the SPC, and SPC2 if used,are copolymers having isotactic propylene sequences. If the FPC ispredominately syndiotactic polypropylene, then the SPC, and the SPC2 ifused, is a copolymer having syndiotactic sequences. It is believed thatthis matching of stereoregularity increases the compatibility of thecomponents results in improved adhesion of the domains of the polymersof different crystallinities in the polymer blend composition.Furthermore, good compatibility is only achieved in a narrow range ofcopolymer composition for the SPC. Narrow intermolecular andintramolecular compositional distribution in the copolymer is preferred.The aforementioned characteristics of the SPC, and SPC2 if used, arepreferably achieved by polymerization with a chiral metallocenecatalyst.

(J) The SPC is made with a polymerization catalyst which formsessentially or substantially isotactic polypropylene when all orsubstantially all propylene sequences in the FPC are isotactic.Nonetheless, the polymerization catalyst used for the formation of SPCwill introduce stereo- and regio-errors in the incorporation ofpropylene. Stereo errors are those where the propylene inserts in thechain with a tacticity that is not isotactic. A regio error in one wherethe propylene inserts with the methylene group or the methyldiene groupadjacent to a similar group in the propylene inserted immediately priorto it. Such errors are more prevalent after the introduction of anethylene in the SPC. Thus, the fraction of propylene in isotacticstereoregular sequences (e.g. triads or pentads) is less than 1 for SPCand decreases with increasing ethylene content of the SPC. While notwanting to be constrained by this theory, we suggest that theintroduction of these errors in the introduction of propylene,particularly in the presence of increasing amounts of ethylene, areimportant in the use of these ethylene propylene copolymers as the SPC.Notwithstanding the presence of these errors, the SPC is statisticallyrandom in the distribution of ethylene.

(K) The SPC is made with a polymerization catalyst which formsessentially or substantially isotactic polypropylene, when all orsubstantially all propylene sequences in the FPC are isotactic. The SPCis statistically random in the distribution of the ethylene andpropylene residues along the chain. Quantitative sequences may beobtained by consideration of the experimentally determined reactivityratios of the second polymer component or by 13 C NMR. The SPC is madewith a single sited metallocene catalyst which allows only a singlestatistical mode of addition of ethylene and propylene in a well-mixed,continuous monomer feed stirred tank polymerization reactor which allowsonly a single polymerization environment for all of the polymer chainsof the SPC.

Generally, without limiting in any way the scope of the invention, onemeans for carrying out a process of the present invention for theproduction of the copolymer second polymer component is as follows: (1)liquid propylene is introduced in a stirred-tank reactor, (2) thecatalyst system is introduced via nozzles in either the vapor or liquidphase, (3) feed ethylene gas is introduced either into the vapor phaseof the reactor, or sparged into the liquid phase as is well known in theart, (4) the reactor contains a liquid phase composed substantially ofpropylene, together with dissolved alpha-olefin, preferably ethylene,and a vapor phase containing vapors of all monomers, (5) the reactortemperature and pressure may be controlled via reflux of vaporizingpropylene (autorefrigeration), as well as by cooling coils, jackets,etc., (6) the polymerization rate is controlled by the concentration ofcatalyst, temperature, and (7) the ethylene (or other alpha-olefin)content of the polymer product is determined by the ratio of ethylene topropylene in the reactor, which is controlled by manipulating therelative feed rates of these components to the reactor.

For example, a typical polymerization process consists of apolymerization in the presence of a catalyst comprising a chiral bis(cyclopentadienyl) metal compound and either 1) a non-coordinatingcompatible anion activator, or 2) an alumoxane activator. An exemplarycatalyst system is described in U.S. Pat. No. 5,198,401 which is hereinincorporated by reference for purposes of U.S. practices. The alumoxaneactivator is preferably utilized in an amount to provide a molaraluminum to metallocene ratio of from about 1:1 to about 20,000:1 ormore. The non-coordinating compatible anion activator is preferablyutilized in an amount to provide a molar ratio of biscyclopentadienylmetal compound to non-coordinating anion of 10:1 to about 1:1. The abovepolymerization reaction is conducted by reacting such monomers in thepresence of such catalyst system at a temperature of from about −50° C.to about 200° C. for a time of from about 1 second to about 10 hours toproduce a copolymer having a weight average molecular weight of fromabout 5,000 or less to about 1,000,000 or more and a molecular weightdistribution of from about 1.8 to about 4.5.

While the process of the present invention includes utilizing a catalystsystem in the liquid phase (slurry, solution, suspension or bulk phaseor combination thereof), gas phase polymerization can also be utilized.When utilized in a gas phase, slurry phase or suspension phasepolymerization, the catalyst systems will preferably be supportedcatalyst systems. See, for example. U.S. Pat. No. 5,057,475 which isincorporated herein by reference for purposes of U.S. practice. Suchcatalyst systems can also include other well-known additives such as forexample, scavengers. See, for example, U.S. Pat. No. 5,153,157 which isincorporated herein by reference for purposes of U.S. practices. Theseprocesses may be employed without limitation of the type of reactionvessels and the mode of conducting the polymerization. As stated above,and while it is also true for systems utilizing a supported catalystsystem, the liquid phase process comprises the steps of contactingethylene and propylene with the catalyst system in a suitablepolymerization diluent and reacting the monomers in the presence of thecatalyst system for a time and at a temperature sufficient to produce anethylene-propylene copolymer of the desired molecular weight andcomposition.

Process Oil

Process oil can be optimally added to the polymer blend compositions ofthe present invention. The addition of process oil in moderate amountslowers the viscosity and flexibility of the blend while improving theproperties of the blend at temperatures near and below OûC. It isbelieved that these benefits arise by the lowering of the Tg of theblend comprising the mixture of the FPC and the SPC. Additional benefitsof adding process oil to the blend of the FPC and the SPC includeimproved processability and a better balance of elastic and tensilestrength are anticipated.

The process oil is typically known as extender oil in the rubberapplication practice. The process oils can consist of (a) hydrocarbonsconsisting of essentially of carbon and hydrogen with traces ofheteroatoms such as oxygen or (b) essentially of carbon, hydrogen and atleast one heteroatom such as dioctyl phthalate, ethers and polyethers.The process oils have a boiling point to be substantially involatile at200° C. These process oils are commonly available either as neat solidsor liquids or as physically absorbed mixtures of these materials on aninert support (e.g. clays, silica) to form a free flowing powder. Webelieve that all forms of these process oils are equally applicable tothe description and the practice of the invention.

The process oils usually include a mixture of a large number of chemicalcompounds which may consist of linear, acyclic but branched, cyclic andaromatic carbonaceous structures. Another family of process oils arecertain low to medium molecular weight (Molecular weight (M_(n))<10,000)organic esters and alkyl ether esters. Examples of process oils areSunpar® 150 and 220 from The Sun Manufacturing Company of Marcus Hook,Pa., USA and Hyprene® V750 and Hyprene V1200 from Ergon, Post Office Box1639, Jackson, Miss. 39215-1639, USA. and IRM 903 from CalumetLubricants Co., 10234 Highway 157, Princeton, La. 71067-9172, USA. It isalso anticipated that combinations of process oils each of which isdescribed above may be used in the practice of the invention. It isimportant that in the selection of the process oil be compatible ormiscible with the polymer blend composition of the FPC and the SPC inthe melt to form a homogenous one phase blend. It is also preferred ifthe process oil is substantially miscible in the SPC at roomtemperature.

The addition of the process oils to the mixture comprising the FPC andthe SPC maybe made by any of the conventional means known to the art.These include the addition of all or part of the process oil prior torecovery of the polymer as well as addition of the process oil, in wholeor in part, to the polymer as a part of a compounding for theinterblending of the FPC and the SPC. The compounding step may becarried out in a batch mixer such as a mill or an internal mixer such asBanbury mixer. The compounding operation may also be conducted in acontinuous process such as a twin screw extruder.

The addition of certain process oils to lower the glass transitiontemperature of blends of isotactic polypropylene and ethylene propylenediene rubber has been described in the art by Ellul in U.S. Pat. Nos.5,290,886 and 5,397,832. We expect these procedures are easilyapplicable to the FPC and SPC mixtures of the current invention.

The FPC and SPC physical mixture may include process oil in the range offrom about 1 to about 200, preferably in the range of from about 2 to 50parts by weight of process oil per hundred parts of total polymer (FPCplus SPC).

The Blend of First and Second Polymer Components

The blends of FPC and SPC and other components may be prepared by anyprocedure that guarantees an intimate mixture of the components. Forexample, the components can be combined by melt pressing the componentstogether on a Carver press to a thickness of about 0.5 millimeter (20mils) and a temperature of about 180° C., rolling up the resulting slab,folding the ends together, and repeating the pressing, rolling, andfolding operation about 10 times. Internal mixers are particularlyuseful for solution or melt blending. Blending at a temperature of about180° C. to 240° C. in a Brabender Plastograph for about 1 to 20 minuteshas been found satisfactory. Still another method that may be used foradmixing the components involves blending the polymers in a Banburyinternal mixer above the flux temperature of all of the components,e.g., 180° C. for about 5 minutes. A complete mixture of the polymericcomponents is indicated by the uniformity of the morphology of thedispersion of FPC and SPC. Continuous mixing may also be used. Theseprocesses are well known in the art and include single and twin screwmixing extruders, static mixers for mixing molten polymer streams of lowviscosity, impingement mixers, as well as other machines and processes,designed to disperse the first polymer component and the second polymercomponent in intimate contact.

The polymer blends of the instant invention exhibit a remarkablecombination of desirable physical properties. The incorporation of aslittle as 5% FPC in the SPC composed of propylene/alpha-olefincopolymers increases the melting point of the blend. In addition, theincorporation of FPC in accordance with the instant invention nearlyeliminates the stickiness characteristic of the propylene/alpha-olefincopolymer alone.

The mechanism by which the desirable characteristics of the presentcopolymer blends are obtained is not fully understood. However, it isbelieved to involve a co-crystallization phenomenon between propylenesequences of similar stereoregularity in the various polymericcomponents, which results in a narrowing of the differences in thecrystallization temperature of the blend components The combined firstpolymer component and second polymer component have a blend meltingpoint closer together than would be expected on a comparison of theproperties of the individual components alone. Surprisingly, some blendcompositions have a single crystallization temperature and a singlemelting temperature, since it would be expected by those skilled in theart that the blending of two crystalline polymers would result in adouble crystallization temperature as well as a double meltingtemperature reflecting the two polymeric components. However, theintimate blending of the polymers having the required crystallinitycharacteristics apparently results in a crystallization phenomenon thatmodifies the other physical properties of the propylene/alpha-olefincopolymer, thus measurably increasing its commercial utility and rangeof applications.

While the above discussion has been limited to the description of theinvention in relation to having only components one and two, as will beevident to those skilled in the art, the polymer blend compositions ofthe present invention may comprise other additives. Various additivesmay be present to enhance a specific property or may be present as aresult of processing of the individual components. Additives which maybe incorporated include, for example, fire retardants, antioxidants,plasticizers, pigments, vulcanizing or curative agents, vulcanizing orcurative accelerators, cure retarders, processing aids, flameretardants, tackifying resins, and the like. These compounds may includefillers and/or reinforcing materials. These include carbon black, clay,talc, calcium carbonate, mica, silica, silicate, combinations thereof,and the like. Other additives which may be employed to enhanceproperties include antiblocking agents, coloring agent. Lubricants, moldrelease agents, nucleating agents, reinforcements, and fillers(including granular, fibrous, or powder-like) may also be employed.Nucleating agents and fillers tend to improve rigidity of the article.The list described herein is not intended to be inclusive of all typesof additives which may be employed with the present invention. Uponreading this disclosure, those of skill in the art will appreciate otheradditives may be employed to enhance properties of the composition. Asis understood by the skilled in the art, the polymer blend compositionsof the present invention may be modified to adjust the characteristicsof the blend as desired.

Morphology of the Blend

The morphology of the blend is shown in Transmission Electron Microscopyof the blends. In this procedure samples were exposed to vapors of 1%aqueous RuO₄ for 3 days. The RuO₄ penetrates the amorphous zones of thecontinuous, less crystalline phase of the polymer while the morecrystalline domains composed largely of the FPC are essentiallyunaffected. Within the continuous zone the RuO₄ stained the microzonesof amorphous polymer while the lamellae of crystalline polymer arevisible by contrast. The blend was cryomicrotomed at −196° C. to thinsections approximately 0.3 to 3 μm thick. Several sections were analyzedfor each sample until a section was found where the crystalline domainswas unstained while the continuous phase was stained to distinguish itfrom the dispersed phase and to observe the microstructure of thelamellae of polymer.

The blends of the current invention with good elastic recovery fromtensile deformation had a microstructure with clearly dispersedmicrodomains of the crystalline phase. This is shown in FIG. 1. Thecomposition and elastic recovery properties of the blend is shown as H7in the Tables below. The domains are elongated with approximatedimensions of 0.2 μm×1 μm. FIG. 2 shows a different blend of theinvention, designated as K7 in the Tables below, with the dispersedphase having dimensions of 0.6 μm×2.0 μm. The addition of SPC2 to thisblend is shown in the micrograph BB7 (FIG. 3) shows the reduction in thesize of the dispersed phase to elongated particles having 0.2 μm foreach dimension. SPC2 is therefore believed to act as an agent forreducing the size of the dispersion of the crystalline phases in thedispersed continuous phase. This is the morphological effect of addingSPC2 to the blend of a FPC and SPC.

Properties of the Blend: Elongation

The blends of the current invention have tensile elongation in excess of700%. This elongation is determined for blends at 20 in/min according tothe procedure described in ASTM D790. The data is reported inengineering units with no correction to the stress for the lateralcontraction in the specimen due to tensile elongation.

The stress-strain elongation properties of the insitu and thecorresponding physical blends was evaluated using dumbbell shapedsample. The samples were compression molded at 180° C. to 200° C. for 15minutes at a force of 15 tons into a plaque of dimensions of 6 in×6 in.The cooled plaques were removed and the specimens were removed with adie. The stress strain evaluation of the samples was conducted on anInstron 4465 tester, made by Instron Corporation of 100 Royall Street,Canton, Mass. The digital data was collected in a file collected by theSeries IX Material Testing System available from Instron Corporation andanalyzed using Excel 5, a spreadsheet program available from MicrosoftCorporation of Redmond, Wash.

FIG. 4 and FIG. 5 show the stress strain elongation data for blendscontaining one FPC and one SPC or two SPC respectively.

Properties of the Blend: Elastic Recovery

The benefit of the above invention is that compositions comprising theFPC and the SPC optionally containing SPC2 and/or amounts of process oilcan be made which have excellent elastic recovery from tensiledeformation. These elastic blends have a morphology of containing acrystalline phase dispersed in the continuous crystallizable phase. Thedispersed crystalline phase contains the majority of the FPC and some ofthe SPCs due to thermodynamic mixing while the continuous phase consistsof the balance of the polymer blend. Elastic recovery from tensiledeformation is a tension set from 200% extension of less than 40%, morepreferably less than 25% and more preferably less than 15%.

These values of the tension set over the range of composition of the FPCand SPC are dependent on the 500% tensile modulus. Elastic recovery ofthe blend is judged on two criteria: (a) extensibility to 500%elongation with a measurable modulus and (b) tension set from anextension to 200% elongation. Comparative blends often cannot beextended to 500% extension for evaluation of the 500% modulus and, thus,cannot be compared to the blends of the current invention. Somecomparative blends in the prior art can be extended to 500% elongationfor the measurement of tensile modulus but have poor elastic recoveryfrom a 200% extension. The elastic blends of the current inventionfulfill both of these conditions. Generally for all blends the tensionset deteriorates with increase in the 500% tensile modulus. Thus tensionset from a 200% extension is judged relative to the tensile modulus ofthe blend for a 500% extension. The blends of the current invention havebetter elastic recovery, as indicated by low tension set, than blends ofthe comparative blends at comparable 500% tensile modulus. Theseproperties are available over a wide range of composition and relativeamounts of the FPC and the SPC. These compositions also have a range oftensile strength from 300 psi to 5000 psi. In the examples shown below,we show examples of numerous blends of composition of the FPC and theSPC which have the above favorable combination of properties.

In one embodiment, the composition of the invention has a tension setfrom 200% extension equal to or less than 0.02 M+5, preferably equal toor less than 0.0108 M+3, more preferably equal to or less than 0.0052M+2, wherein M is 500% modulus expressed in lbs/inch².

It is possible to generate comparative polymer blends with some aspectof the combined 500% tensile modulus and 200% tension set properties ofthe blends of this invention approached if the SPCs are of extremelyhigh molecular weight and in the limit crosslinked. Such a combinationwould lead to blends which had very poor processing characteristicssince they would tend to melt fracture. It is understood that thosepolymer blends are directed to easy processing materials that can behandled in conventional thermoplastics processing machinery.

Another part of the invention is that the elastic recovery referred toabove can be enhanced by the thermal annealing of the polymer blends orby the orientation of articles made from these polymer blends. Thermalannealing of the polymer blend is conducted by maintaining the polymerblends or the articles made from a such a blend at temperature betweenroom temperature to a maximum of 160° C. or more preferably to a maximumof 130° C. for a period between 5 minutes to less than 7 days. A typicalannealing period is 3 days at 50° C. or 5 minutes at 100° C. Theannealing time and temperature can be adjusted for any particular blendcomposition comprising a FPC and one or two SPC by experimentation. Itis believed that during this annealing process, there is intermolecularrearrangement of the polymer chains leading to a material with muchgreater recovery from tensile deformation than the unannealed material.The elastic recovery of annealed/aged blends of this invention is shownin FIG. 6.

Another part of the invention is that the mechanical properties referredto above can be enhanced by the mechanical orientation of the polymerblend. Mechanical orientation can be done by the temporary, forcedextension of the polymer blend along one or more axis for a short periodof time before it is allowed to relax in the absence of the extensionalforces. It is believed that the mechanical orientation of the polymerleads to reorientation of the crystallizable portions of the blend ofthe first and the second polymer. Oriented polymer blends is conductedby maintaining the polymer blends or the articles made from a such ablend at an extension of 10% to 400% for a period of 0.1 seconds to 24hours. A typical orientation is an extension of 200% for a momentaryperiod at room temperature. The elastic recovery of oriented blends ofthis invention is shown in FIG. 7.

In one embodiment, articles can contain the composition of the inventionafter the composition has been oriented, and wherein the tension setfrom 200% extension equal to or less than 0.011 M+3, preferably equal toor less than 0.0057M+2, more preferably equal to or less than 0.0035M+1,wherein M is 500% modulus expressed in lbs/inch².

Annealing and orientation of the blend of the FPC and SPC lead toimprovement in the tensile recovery properties of the blend. This isshown in the data in Tables below where the tension set recovery valuesfor the blends described in the invention are described for the blendsas made, after annealing and after orientation as described in theprocedures above. The data show that the elastic recovery properties areenhanced.

Properties of the Blend: Flexural Modulus

The benefit of the above invention is that compositions comprising theFPC and the SPC containing optional amounts of process oil can be madewhich have low flexural modulus. These blends have a crystalline phasedispersed in the continuous crystallizable phase. The crystalline phasecontains the majority of the FPC and some of the SPCs due tothermodynamic mixing while the continuous phase consists of the balanceof the polymer blend. Low flexural modulus is a 1% secant modulus lessthan 60 kpsi in/in, more preferably less than 30 kpsi in/in and morepreferably less than 15 kpsi in/in.

These values of the flexural modulus over the range of composition ofthe FPC and SPC are dependent on the 500% tensile modulus. Flexuralmodulus of the blend is judged on two criteria: (a) extensibility to500% elongation with a measurable modulus and (b) 1% secant flexuralmodulus. Comparative blends often cannot be extended to 500% extensionfor evaluation of the 500% modulus and thus cannot be compared to theblends of the current invention. The flexible blends of the currentinvention fulfill both of these conditions. Generally for all blends theflexural modulus deteriorates with increase in the 500% tensile modulus.Thus flexural modulus is judged relative to the tensile modulus of theblend for a 500% extension. The blends of the current invention have alower flexural modulus, as indicated by low tension set, than blends ofthe comparative blends at comparable 500% tensile modulus. Theseproperties are available over a wide range of composition and relativeamounts of the FPC and the SPC. In the examples shown below we showexamples of numerous blends of composition of the FPC and the SPC whichhave the above favorable combination of properties.

The dependence of the flexural modulus of the blend of this invention asa correlated function of the 500% tensile modulus is shown FIG. 8.

In one embodiment, the composition of the invention has a flexuralmodulus in kpsi.in/in equal to or less than 0.013 M-1.3, preferablyequal to or less than 0.0083 M-1.6, more preferably equal to or lessthan 0.0062 M-2.5 wherein M is 500% modulus expressed in lbs/inch².

In another embodiment, articles can contain the composition of theinvention after the composition has been oriented, and wherein theflexural modulus in kpsi.in/in equal to or less than 0.013 M-1.3,preferably equal to or less than 0.0083 M-1.6, more preferably equal toor less than 0.0062M-2.5 wherein M is 500% modulus expressed inlbs/inch².

As used herein, Mooney Viscosity was measured as ML (1+4) at 125° C. inMooney units according to ASTM D1646.

The composition of Ethylene propylene copolymers, which are used ascomparative examples, was measured as ethylene Wt. % according to ASTM D3900.

The composition of the second polymer component was measured as ethyleneWt. % according to the following technique. A thin homogeneous film ofthe second polymer component, pressed at a temperature of about orgreater than 150° C. was mounted on a Perkin Elmer PE 1760 infra redspectrophotometer. A fill spectrum of the sample from 600 cm-1 to 400cm-1 was recorded and the ethylene Wt. % of the second polymer componentwas calculated according to Equation 1 as follows:ethylene Wt. %=82.585−111.987X+30.045X ²wherein X is the ratio of the peak height at 1155 cm⁻¹ and peak heightat either 722 cm⁻¹ or 732 cm⁻¹, which ever is higher.

Techniques for determining the molecular weight (Mn and Mw) andmolecular weight distribution (MWD) are found in U.S. Pat. No. 4,540,753(Cozewith, Ju and Verstrate) (which is incorporated by reference hereinfor purposes of U.S. practices) and references cited therein and inMacromolecules, 1988, volume 21, p 3360 (Verstrate et al) (which isherein incorporated by reference for purposes of U.S. practice) andreferences cited therein.

The procedure for Differential Scanning Calorimetry is described asfollows. About 6 to 10 mg of a sheet of the polymer pressed atapproximately 200° C. to 230° C. is removed with a punch die. This isannealed at room temperature for 240 hours. At the end of this period,the sample is placed in a Differential Scanning Calorimeter (PerkinElmer 7 Series Thermal Analysis System) and cooled to about −50° C. toabout −70° C. The sample is heated at 20° C./min to attain a finaltemperature of about 200° C. to about 220° C. The thermal output isrecorded as the area under the melting peak of the sample which istypically peaked at about 30° C. to about 175° C. and occurs between thetemperatures of about 0° C. and about 200° C. is measured in Joules as ameasure of the heat of fusion. The melting point is recorded as thetemperature of the greatest heat absorption within the range of meltingof the sample. Under these conditions, the melting point of the secondpolymer component and the heat of fusion is lower than the first polymercomponent as outlined in the description above.

Composition distribution of the second polymer component was measured bythe thermal fractionation as described below. About 30 gms of the secondpolymer component was cut into small cubes about ⅛″ on the side. This isintroduced into a thick walled glass bottle closed with screw cap alongwith 50 mg of Irganox1076, an antioxidant commercially available fromCiba-Geigy Corporation. Then, 425 ml of hexane (a principal mixture ofnormal and isomers) is added to the contents of the bottle and thesealed bottle is maintained at about 23° C. for 24 hours. At the end ofthis period, the solution is decanted and the residue is treated withadditional hexane for an additional 24 hours. At the end of this period,the two hexane solutions are combined and evaporated to yield a residueof the polymer soluble at 23° C. To the residue is added sufficienthexane to bring the volume to 425 ml and the bottle is maintained atabout 31° C. for 24 hours in a covered circulating water bath. Thesoluble polymer is decanted and the additional amount of hexane is addedfor another 24 hours at about 31° C. prior to decanting. In this manner,fractions of the second polymer component soluble at 40° C., 48° C., 55°C. and 62° C. are obtained at temperature increases of approximately 8°C. between stages. Further, increases in temperature to 95° C. can beaccommodated, if heptane, instead of hexane, is used as the solvent forall temperatures above about 60° C. The soluble polymers are dried,weighed and analyzed for composition, as wt. % ethylene content, by theIR technique described above. Soluble fractions obtained in the adjacenttemperature increases are the adjacent fractions in the specificationabove.

Comparative data was obtained with EPR which is Vistalon 457, sold bythe Exxon Chemical Company, Houston Tex.

Blends were made by mixing a total of 72 g of all components, includingthe first polymer component, the second polymer component, the optionalamounts of process oil and other ingredients in a Brabender intensivemixture for 3 minutes at a temperature controlled to be within 185° C.and 220° C. High shear roller blades were used for the mixing andapproximately 0.4 g of Irganox-1076, an antioxidant available from theNovartis Corporation, was added to the blend. At the end of the mixing,the mixture was removed and pressed out into a 6″×6″ mold into a pad025″ thick at 215° C. for 3 to 5 minutes. At the end of this period, thepad was cooled and removed and allowed to anneal for 1 day. Testspecimens of the required dumbbell geometry were removed from this padand evaluated on an Instron 4465 tester equipped with Instron Series IXSoftware for Windows to produce the mechanical deformation data. TheInstron Tester and associated equipment is available form The InstronCorporation in Canton, Mass. The testing was done at a travel rate of20″/min and all data is reported in engineering stress and strain termwith values of the stress uncorrected for the contraction in the crosssection of the sample being tested.

Samples were aged by allowing them to stand at room temperature prior totesting. Samples were aged for 5, 10, 15, 20 and 25 days prior totesting on the Instron. Significant difference in the tensile strengthand tension set were observed between samples aged 1 days versus thoseaged for 5 or more days. There was no experimental difference betweensamples aged 5 days or longer.

Samples were oriented by momentarily extending them to 200% extension atroom temperature. These oriented samples were retested under tensiletesting conditions outlined above. Tension set was determined on thesamples of the blend which has been extended on the Instron tester to200% extension and then allowed to relax. The samples were removed andthe length (L2) of the deformation zone, between the grips on theInstron tester, was measured after 10 minutes. The original distancebetween the rips was the original length (L1) of the deformation zone.The tension set (TSet) is given by the formulaTset=100*(L2−L1)/L1

Flexural modulus was determined for samples of the blend by ASTMprocedure D790 at room temperature.

The invention, while not meant to be limited thereby, is furtherillustrated by the following specific examples:

EXAMPLES Example 1 Ethylene/Propylene Copolymerization to Form theSecond Polymer Component

Continuous Polymerization of the SPC was conducted in a 9 literContinuous Flow Stirred Tank Reactor using hexane as the solvent. Theliquid full reactor had a residence time of 9 minutes and the pressurewas maintained at 700 kpa. A mixed feed of Hexane, ethylene andpropylene was pre-chilled to approximately −30° C. to remove the heat ofpolymerization, before entering the reactor. Solution ofcatalyst/activator in Toluene and the scavenger in hexane wereseparately and continuously admitted into the reactor to initiate thepolymerization. The reactor temperature was maintained between 35 and 50C, depending on the target molecular weight. The feed temperature wasvaried, depending on the polymerization rate to maintain a constantreactor temperature. The polymerization rate was varied from about 0.5Kg/hr to about 4 Kg/hr.

Hexane at 30 Kg/hr was mixed with ethylene at 717 g/hr and propylene at5.14 Kg/hr and fed to the reactor. The polymerization catalyst, dimethylsilyl bridged bis-indenyl Hafnium dimethyl activated 1:1 molar ratiowith N′,N′-Dimethyl anilinium-tetrakis(pentafluorophenyl)borate wasintroduced at the rate of at 0.0135 g/hr. A dilute solution oftriisobutyl aluminum was introduced into the reactor as a scavenger ofcatalyst terminators: a rate of approximately 111 mole of scavenger permole of catalyst was adequate for this polymerization. After fiveresidence times of steady polymerization, a representative sample of thepolymer produced in this polymerization was collected. The solution ofthe polymer was withdrawn from the top, and then steam distilled toisolate the polymer. The polymerization rate was measured at 3.7 Kg/hr.The polymer produced in this polymerization had an ethylene content of14%, ML (1+4) 125 C of 13.1 and had isotactic propylene sequences.

Variations in the composition of the polymer were obtained principallyby changing the ratio of ethylene to propylene. Molecular weight of thepolymer was varied by either changing the reactor temperature or bychanging the ratio of total monomer feed rate to the polymerizationrate. Dienes for terpolymerization were added to the mixed feed streamentering the reactor by preparing the diene in a hexane solution andmetering it in the required volumetric amount.

Example 2 Comparative Ethylene/Propylene Polymerization where thePropylene Residues are Atactic

Polymerizations were conducted in a 1 liter thermostated continuous feedstirred tank reactor using hexane as the solvent. The polymerizationreactor was full of liquid. The residence time in the reactor wastypically 7-9 minutes and the pressure was maintained at 400 kpa.Hexane, ethene and propene were metered into a single stream and cooledbefore introduction into the bottom of the reactor. Solutions of allreactants and polymerization catalysts were introduced continuously intothe reactor to initiate the exothermic polymerization. Temperature ofthe reactor was maintained at 45° C. by changing the temperature of thehexane feed and by using cooling water in the external reactor jacket.For a typical polymerization, the temperature of feed was about −10° C.Ethene was introduced at the rate of 45 gms/min and propene wasintroduced at the rate of 310 gms/min. The polymerization catalyst,dimethyl silyl bridged (tetramethylcyclopentadienyl) cyclododecylamidotitanium dimethyl activated 1:1 molar ratio with N′,N′-Dimethylanilinium-tetrakis(pentafluorophenyl)borate was introduced at the rateof 0.002780 gms/hr. A dilute solution of triisobutyl aluminum wasintroduced into the reactor as a scavenger of catalyst terminators: arate of approximately 36.8 mole per mole of catalyst was adequate forthis polymerization. After five residence times of steadypolymerization, a representative sample of the polymer produced in thispolymerization was collected. The solution of the polymer was withdrawnfrom the top, and then steam distilled to isolate the polymer. The rateof formation of the polymer was 258 gms/hr. The polymer produced in thispolymerization had an ethylene content of 14.1 wt. %, ML@125 (1+4) of95.4.

Variations in the composition of the polymer were obtained principallyby changing the ratio of ethene to propene. Molecular weight of thepolymer could be increased by a greater amount of ethene and propenecompared to the amount of the polymerization catalyst. These polymersare described as aePP in the Tables below.

Example 3 Analysis and Solubility of Several Second Polymer Components

In the manner described in Example 1 above, several second polymercomponents of the above specification were synthesized. These aredescribed in the table below. Table 1 describes the results of the GPC,composition, ML and DSC analysis for the polymers. TABLE 1 Ethylene Heatof ML (Mw) by wt. % fusion Melting Point (1 + 4)@ SPC (Mn) by GPC GPC byIR J/g by DSC (° C.) 125° C. SPC-1 102000 248900 7.3 71.9 84.7 14 SPC-29.4 30.2 65.2 27.8 SPC-3 124700 265900 11.6 17.1 43.0 23.9 SPC-4 12.816.4 42.5 SPC-5 14.7 13.2 47.8 38.4 SPC-6 121900 318900 16.4  7.8 40.333.1 SPC-7 17.8  5.3 39.5 Comparative Polymers EPR 47.8 not not 40detected detected AePP 11.7 not not 23 detected detected

Table 1: Analysis of the second polymer component and the comparativepolymers Table 2 describes the solubility of the second polymercomponent TABLE 2 Wt. % Wt. % Wt. % Wt. % soluble at soluble at solubleat soluble SPC 23° C. 31° C. 40° C. at 48° C. SPC-1 1.0 2.9 28.3 68.5SPC-3 6.5 95.7 SPC-6 51.6 52.3 2.6 SPC-5 36.5 64.2 Comparative PolymersEPR 101.7 aePP 100.5

Table 2: Solubility of fractions of the second polymer component. Sum ofthe fractions add up to slightly more than 100 due to imperfect dryingof the polymer fractions.

Table 3 describes the composition of the fractions of the second polymercomponent obtained in Table 2. Only fractions which have more than 4% ofthe total mass of the polymer have been analyzed for composition. TABLE3 Composition: Wt. % ethylene in fraction soluble soluble solublesoluble soluble SPC at 23° C. at 31° C. at 40° C. at 48° C. at 56° C.SPC-1 8.0 7.6 SPC-3 12.0 11.2 SPC-6 16.8 16.5 SPC-5 14.9 14.6Comparative EPR 46.8 Atactic ePP 11.8

Table 3: Composition of fractions of the second polymer componentobtained in Table 2. The experimental inaccuracy in determination of theethylene content is believed to about 0.4 wt. % absolute.

Example 4

Blends were made in all composition of Table 4 according to theprocedure described above. TABLE 4 Flexural Modulus, Tensile Modulus andTension set for Binary Blends of one FPC and one SPC as molded 500% 100%Flexural C2 Wt. Modulus Modulus modulus Sample Wt % SPC1 ML of SPC1 % ofSPC1 (psi) (MPa) (psi) (Mpa) (kpsi in/in) (MPa cm/cm) F6 66.7 11.5 12.41778 12.26 1168 8.05 F7 77.8 11.5 12.4 1442 9.94 813 5.61 F8 88.9 11.512.4 1077 7.43 575 3.96 F9 100 11.5 12.4 971 6.69 471 3.25 G6 66.7 18.312.1 1800 12.41 1138 7.85 G7 77.8 18.3 12.1 1446 9.97 741 5.11 G8 88.918.3 12.1 1089 7.51 538 3.71 G9 100 18.3 12.1 979 6.75 472 3.25 H6 66.725.3 12.0 1969 13.58 1216 8.38 18.1 0.12 H7 77.8 25.3 12.0 1591 10.97879 6.06 10.1 0.07 H8 88.9 25.3 12.0 1254 8.65 664 4.58 5.5 0.04 H9 10025.3 12.0 1127 7.77 552 3.81 3.8 0.03 J6 66.7 39.7 13.4 1495 10.31 9776.74 J7 77.8 39.7 13.4 1394 9.61 754 5.20 J8 88.9 39.7 13.4 904 6.23 4523.12 J9 100 39.7 13.4 751 5.18 320 2.21 K5 55.6 28.9 14.8 1720 11.861297 8.94 23.1 0.16 K6 66.7 28.9 14.8 1471 10.14 990 6.83 7.7 0.05 K777.8 28.9 14.8 1251 8.63 621 4.28 3.9 0.03 K8 88.9 28.9 14.8 763 5.26306 2.11 1.8 0.01 K9 100 28.9 14.8 387 2.67 200 1.38 1.3 0.01 L6 66.733.1 16.4 1133 7.81 613 4.23 L7 77.8 33.1 16.4 704 4.85 293 2.02 L8 88.933.1 16.4 573 3.95 187 1.29 L9 100 33.1 16.4 91 0.63 96 0.66 M6 66.725.6 17 996 6.87 597 4.12 4.2 0.03 M7 77.8 25.6 17 698 4.81 298 2.05 1.80.01 M8 88.9 25.6 17 336 2.32 185 1.28 1.0 0.01 M9 100 25.6 17 129 0.89135 0.93 0.8 0.01 N8 88.9 34.5 11.1 1506 10.38 851 5.87 N9 100 34.5 11.11412 9.74 675 4.65 P8 88.9 16.4 10.8 1405 9.69 805 5.55 7.4 0.05 P9 10016.4 10.8 1268 8.74 641 4.42 5.7 0.04

In this example blends of a First Polymeric Component, Escorene 4292, ahomoisotactic polypropylene available from Exxon Chemical Co., HoustonTex. and one Second Polymeric component (identified as SPC1 in Table 4)were made using the procedure as described above The blends were made ina different composition range as shown by the table above. All of thecompositions are within have the properties of this invention.Properties of the blend were measured as molded.

Example 5

TABLE 5 Flexural Modulus, Tensile Modulus and Tension set for BinaryBlends of one FPC and two SPC as molded 500% 100% Flexural C2 Wt.Modulus Modulus modulus Sample Wt % SPC1 ML of SPC1 % of SPC1 Wt. % SPC2(psi) (MPa) (psi) (Mpa) (kpsi in/in) (MPa cm/cm) AA4 44.4 31.2 13.4 27.81833 12.64 1096 7.56 16.6 0.11 AA5 55.6 31.2 13.4 22.2 1571 10.83 9096.27 11.3 0.08 AA6 66.7 31.2 13.4 16.7 1342 9.25 748 5.16 7.9 0.05 AA777.8 31.2 13.4 11.1 1077 7.43 524 3.61 4.7 0.03 AA8 88.9 31.2 13.4 5.56872 6.01 385 2.65 3.4 0.02 AA9 100 31.2 13.4 0 751 5.18 320 2.21 BB444.4 38.4 14.7 27.8 1791 12.35 1154 7.96 17.4 0.12 BB5 55.6 38.4 14.722.2 1543 10.64 798 5.50 13.8 0.10 BB6 66.7 38.4 14.7 16.7 1187 8.18 5483.78 4.8 0.03 BB7 77.8 38.4 14.7 11.1 920 6.34 379 2.61 2.9 0.02 BB888.9 38.4 14.7 5.56 697 4.81 386 2.66 1.9 0.01 BB9 100 38.4 14.7 0 3872.67 200 1.38 CC5 55.6 24.9 12.1 22.2 1619 11.16 970 6.69 17.4 0.12 CC666.7 24.9 12.1 16.7 1504 10.37 849 5.85 12.1 0.08 CC7 77.8 24.9 12.111.1 1296 8.94 690 4.76 8.7 0.06 CC8 88.9 24.9 12.1 5.56 1152 7.94 5814.01 5.8 0.04 CC9 100 24.9 12.1 0 1051 7.25 481 3.32 4.6 0.03 EE5 55.631.2 13.4 13.32 2019 13.92 1303 8.98 EE6 66.7 31.2 13.4 10.02 1581 10.90878 6.05 EE7 77.8 31.2 13.4 6.66 1398 9.64 643 4.43 EE8 88.9 31.2 13.43.33 1064 7.34 457 3.15 EE9 100 31.2 13.4 0 871 6.01 381 2.63 FF5 55.638.4 14.7 13.32 1830 12.62 1214 8.37 22.0 0.15 FF6 66.7 38.4 14.7 10.021612 11.11 847 5.84 8.4 0.06 FF7 77.8 38.4 14.7 6.66 1168 8.05 470 3.244.1 0.03 FF8 88.9 38.4 14.7 3.33 921 6.35 369 2.54 2.5 0.02 FF9 100 38.414.7 0 579 3.99 264 1.82 2.0 0.01 DD4 44.4 23.4 16.8 27.8 1640 11.311053 7.26 13.2 0.09 DD5 55.6 23.4 16.8 22.2 1424 9.82 708 4.88 6.2 0.04DD6 66.7 23.4 16.8 16.7 1178 8.12 437 3.01 2.5 0.02 DD7 77.8 23.4 16.811.1 849 5.85 270 1.86 1.4 0.01 DD8 88.9 23.4 16.1 5.56 535 3.69 1991.37 1.1 0.01 DD9 100 23.4 16.1 0 318 2.19 135 0.93 GG6 66.7 24.9 12.110.02 1751 12.07 975 6.72 GG7 77.8 24.9 12.1 6.66 1563 10.78 798 5.50GG8 88.9 24.9 12.1 3.33 1279 8.82 624 4.30 GG9 100 24.9 12.1 0 1129 7.78552 3.81 HH5 55.6 23.4 16.8 13.32 1385 9.55 964 6.65 13.1 0.09 HH6 66.723.4 16.8 10.02 1005 6.93 501 3.45 4.0 0.03 HH7 77.8 23.4 16.8 6.66 5313.66 251 1.73 1.9 0.01 HH8 88.9 23.4 16.8 3.33 318 2.19 184 1.27 1.10.01 HH9 100 23.4 16.8 0 129 0.89 135 0.93 JJ6 66.7 31.2 13.4 3.33 156910.82 889 6.13 JJ7 77.8 31.2 13.4 2.22 1303 8.98 603 4.16 JJ8 88.9 31.213.4 1.11 1007 6.94 417 2.88 JJ9 100 31.2 13.4 0 753 5.19 320 2.21 KK555.6 38.4 14.7 4.44 1943 13.40 1316 9.07 KK6 66.7 38.4 14.7 3.33 166611.49 871 6.01 KK7 77.8 38.4 14.7 2.22 1295 8.93 507 3.50 KK8 88.9 38.414.7 1.11 976 6.73 383 2.64 KK9 100 38.4 14.7 0 387 2.67 200 1.38 LL666.7 24.9 12.1 3.33 1944 13.40 1121 7.73 LL7 77.8 24.9 12.1 2.22 159911.02 854 5.89 LL8 88.9 24.9 12.1 1.11 1259 8.68 638 4.40 LL9 100 24.912.1 0 1127 7.77 552 3.81

In this example blends of a First Polymeric Component, Escorene 4292, ahomoisotactic polypropylene available from Exxon Chemical Co. HoustonTex. and two Second Polymeric component (identified as SPC1 and SPC2 inTable 5) were made using the procedure as described above. The SPC2 hasa ML(1+4)@125 of 14 and an ethylene content of 7.3 wt. %. Thecomposition and the ML of the SPC1 are indicated in the Table for thevarious SPC1 used. The blends were made in a different composition rangeas shown by the table above. All of the compositions are within have theproperties of this invention. Properties of the blend were measured asmolded.

Example 6

TABLE 6 Hysteresis and Tension set for Binary Blends of one FPC and oneSPC and Ternary Blend of one FPC and two SPC described in Table 4 and 5as (1) new, (2) after annealing at room temperature for 21 days and (3)after momentary orientation to 200%. 200% Hysterisis Set Tension Set %Sample New Annealed Oriented New Annealed Oriented F6 55 56 31 28 27 6F7 35 29 16 19 16 6 F8 20 24 15 16 9 6 F9 18 16 6 9 3 3 H6 65 64 31 3431 13 H7 38 36 16 19 19 6 H8 33 25 16 16 13 3 H9 21 21 13 14 6 2 M5 9171 54 42 31 16 M6 65 48 41 25 9 9 M7 38 28 29 9 6 3 M8 33 24 23 6 3 3 M932 19 20 9 3 2 N8 52 13 13 31 6 6 N9 57 33 32 38 16 19 P7 57 54 57 38 2713 P8 39 34 34 25 22 10 P9 33 23 23 25 16 6 G6 60 56 31 28 25 13 G7 3331 16 19 16 6 G8 24 28 8 13 9 3 G9 12 13 6 8 9 3 J6 47 21 21 19 9 9 J731 24 16 13 11 6 J8 18 13 7 13 9 6 J9 15 9 3 6 6 2 K5 71 79 48 34 41 16K6 48 33 25 52 16 9 K7 19 15 11 9 9 2 K8 14 13 1 6 6 0 K9 16 8 6 5 3 0L6 60 35 21 25 13 8 L7 39 20 14 9 3 5 L8 31 15 5 8 8 3 L9 31 31 9 9 0 3AA4 65 54 43 33 28 14 AA5 40 39 20 25 19 8 AA6 27 31 16 22 16 5 AA7 1919 11 16 13 5 AA8 17 14 13 13 9 2 BB4 53 56 35 28 28 9 BB5 37 36 19 1919 6 BB6 23 15 16 14 9 6 BB7 14 20 5 11 6 5 BB8 14 18 10 9 6 3 CC5 58 4930 34 25 16 CC6 43 41 20 22 16 8 CC7 29 24 15 19 13 6 CC8 28 20 11 17 96 EE5 60 56 60 31 42 11 EE6 35 26 35 17 14 6 EE7 21 14 21 13 9 5 EE8 1614 16 9 6 2 FF4 88 81 64 50 38 25 FF5 52 48 31 30 23 13 FF6 23 23 15 139 6 FF7 19 11 5 9 6 3 FF8 9 8 5 6 3 2 DD4 65 56 39 31 23 6 DD5 34 34 2616 25 6 DD6 28 23 20 11 17 3 DD7 24 23 20 9 13 3 DD8 28 24 15 6 9 0 GG643 43 43 25 25 9 GG7 28 28 28 19 16 9 GG8 22 22 22 16 13 6 HH4 79 79 5445 41 19 HH5 64 64 39 34 28 11 HH6 38 34 26 16 11 5 HH7 28 30 21 9 6 2HH8 26 25 15 6 3 0 JJ5 73 73 73 41 38 19 JJ6 35 35 35 19 16 8 JJ7 17 1717 13 9 5 JJ8 13 13 13 9 6 5 KK5 56 64 39 31 28 11 KK6 30 26 19 17 13 5KK7 18 11 9 9 6 2 KK8 11 12 6 9 6 2 LL6 60 60 60 34 31 13 LL7 32 32 3219 16 8 LL8 26 26 26 16 13 6

Example 7

Blends were made in all composition of Table 7 according to theprocedure described above. TABLE 7 Blends where the FPC is a reactorcopolymer and the SPC are described below 500% 100% Modulus ModulusSample Wt % SPC1 Wt % FPC (psi) (MPa) (psi) (MPa) 2AA1 44.4 44.4 2AA238.8 38.8 2AA3 33.3 33.3 2AA4 27.8 27.8 1302 8.98 919 6.34 2AA5 22.222.2 1194 8.23 794 5.47 2AA6 16.7 16.7 1013 6.98 604 4.16 2AA7 11.1 11.1857 5.91 486 3.35 2AA8 5.55 5.55 690 4.76 353 2.43 2BB1 27 62 2BB2 23 542BB3 20 47 2BB4 17 39 1311 9.04 994 6.85 2BB5 13 31 125 0.86 821 5.662BB6 10 23 1006 6.94 591 4.07 2BB7 7 16 823 5.67 438 3.02 2BB8 3 8 6574.53 338 2.33

In this example blends of a First Polymeric Component, Escorene 9272, areactor copolymer available from Exxon Chemical Co., Houston Tex. havingan ethylene content of 5 wt % and 2.9 MFR and two Second Polymericcomponent (identified as SPC1 and SPC2 in Table 7) were made using theprocedure as described above. The SPC1 has a ML(1+4)@ 125 of 11 and anethylene content of 14.5 wt %. The SPC2 has a ML(1+4)@125 of 21 and anethylene content of 5.8 wt %. The blends were made in a differentcomposition range as shown by the table above. All of the compositionsare within have the properties of this invention. Properties of theblend were measured as molded.

Example 8

TABLE 8 Hysteresis and Tension set for Binary Blends of one FPC and oneSPC and Ternary Blend of one FPC and two SPC described in Table 7 as (1)new, (2) after annealing at room temperature for 21 days and (3) aftermomentary orientation to 200%. 200% Hysterisis Set Tension Set % SampleNew Annealed Oriented New Annealed Oriented 2AA4 63 63 33 29 37 6 2AA539 39 28 20 22 9 2AA6 31 29 15 17 16 3 2AA7 26 26 11 11 12 3 2AA8 18 159 8 9 3 2BB4 63 71 39 40 34 18 2BB5 44 43 28 37 19 12 2BB6 26 31 15 1212 4 2BB7 19 20 11 9 11 3 2BB8 18 18 10 9 11 3

Example 9

Blends were made in all composition of Table 7 according to theprocedure described above. TABLE 9 Blends where the FPC is a reactorcopolymer and the SPC are described below 500% 100% Modulus ModulusSample Wt % SPC1 Wt % FPC (psi) (MPa) (psi) (MPa) 2CC1 44.4 44.4 2CC238.8 38.8 2CC3 33.3 33.3 2CC4 27.8 27.8 1524 10.51 1082 7.46 2CC5 22.222.2 1261 8.69 733 5.05 2CC6 16.7 16.7 1119 7.72 581 4.01 2CC7 11.1 11.1854 5.89 411 2.83 2CC8 5.55 5.55 656 4.52 304 2.10 2DD1 27 62 2DD2 23 542DD3 20 47 2DD4 17 39 1647 11.36 1314 9.06 2DD5 13 31 1452 10.01 8345.75 2DD6 10 23 1196 8.25 610 4.21 2DD7 7 16 885 6.10 388 2.68 2DD8 3 8670 4.62 283 1.95

In this example blends of a First Polymeric Component, Escorene 7132, aimpact copolymer available from Exxon Chemical Co., Houston Tex. havingan ethylene content of 9 wt % and 2.0 MFR and two Second Polymericcomponent (identified as SPC1 and SPC2 in Table 7) were made using theprocedure as described above. The SPC1 has a ML(1+4)@125 of 11 and anethylene content of 14.5 wt %. The SPC2 has a ML(1+4)@125 of 21 and anethylene content of 5.8 wt %. The blends were made in a differentcomposition range as shown by the table above. All of the compositionsare within have the properties of this invention. Properties of theblend were measured as molded.

Example 10

TABLE 10 Hysteresis and Tension set for Binary Blends of one FPC and oneSPC and Ternary Blend of one FPC and two SPC described in Table 9 as (1)new, (2) after annealing at room temperature for 21 days and (3) aftermomentary orientation to 200%. 200% Hysterisis Set Tension Set % SampleNew Annealed Oriented New Annealed Oriented 2CC4 66 77 39 37.5 34.37514.0625 2CC5 44 41 28 23.4375 18.75 4.6875 2CC6 25 31 16 10.9375 9.3753.125 2CC7 18 18 10 10.9375 9.375 3.125 2CC8 19 19 11 9.375 7.81251.5625 2DD4 89 89 58 53.125 34.375 25 2DD5 44 40 26 20.3125 18.75 6.252DD6 31 28 16 10.9375 10.9375 4.6875 2DD7 18 19 9 7.8125 7.8125 3.1252DD8 21 19 11 4.6875 6.25 3.125

Example 11

Blends were made in all composition of Table 11 according to theprocedure described above. TABLE 11 Blends where the FPC is an isotactichomopolymer, a process oil and the SPC are described below 500% 100%Modulus Modulus Sample Wt % SPC1 Wt % FPC Wt % Sunpar 150 (psi) (MPa)(psi) (MPa) 2EE1 36 36 20 2EE2 31 31 20 1355 9.34 1130 7.79 2EE3 27 2720 1248 8.60 945 6.52 2EE4 22 22 20 1119 7.72 749 5.16 2EE5 18 18 20 9026.22 532 3.67 2EE6 13 13 20 690 4.76 336 2.32 2EE7 9 9 20 576 3.97 2741.89 2EE8 4 4 20 386 2.66 176 1.21 2EE9 0 0 20 221 1.52 121 0.83 2FF1 2150 20 2FF2 19 44 20 1552 10.70 1313 9.05 2FF3 16 37 20 1442 9.94 11137.67 2FF4 13 31 20 1264 8.71 831 5.73 2FF5 11 25 20 1025 7.07 569 3.922FF6 8 19 20 798 5.50 387 2.67 2FF7 5 12 20 605 4.17 269 1.85 2FF8 3 620 406 2.80 176 1.21

In this example blends of a First Polymeric Component, Escorene 4292, aisotactic homopolymer available from Exxon Chemical Co., Houston Tex.having 0.9 MFR and two Second Polymeric component (identified as SPC1and SPC2 in Table 7) were made using the procedure as described above.The SPC1 has a ML(1+4)@125 of 11 and an ethylene content of 14.5 wt,%.The SPC2 has a ML(1+4)@125 of 21 and an ethylene content of 5.8 wt %.Sunpar 150 is a process oil available from Sun Refining Company. Theblends were made in a different composition range as shown by the tableabove. All of the compositions are within have the properties of thisinvention. Properties of the blend were measured as molded.

Example 12

TABLE 12 Hysteresis and Tension set for Ternary Blend of one FPC and twoSPC and a process oil described in Table 11 as (1) new, (2) afterannealing at room temperature for 21 days and (3) after momentaryorientation to 200%. 200% Tension Hysterisis Set Set % Sample NewAnnealed Oriented New Annealed Oriented EE3 58 58 43 31.25 28.12510.9375 EE4 43 46 31 21.875 21.875 7.8125 EE5 36 36 21 15.625 17.18754.6875 EE6 25 26 15 10.9375 12.5 4.6875 EE7 18 19 11 7.8125 10.93754.6875 EE8 16 18 9 4.6875 7.8125 3.125 EE9 11 13 14 1.5625 4.6875 0 FF376 76 53 39.0625 37.5 15.625 FF4 58 53 36 28.125 26.5625 7.8125 FF5 3838 29 15.625 17.1875 7.8125 FF6 29 24 21 10.9375 10.9375 6.25 FF7 20 1911 7.8125 7.8125 3.125 FF8 16 18 11 6.25 6.25 3.125

Example 12 Comparative Blends

Comparative blends of compositions similar to those of the blends of theinventive composition were made with EPR and aePP as shown in Table 1.In all cases the blends had a tensile elongation less than 500% and arenot reported in either the FIGS. 6, 7 and 8.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present invention,including all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

1-31. (canceled)
 32. A blend comprising at least one polymer (A) and atleast one polymer (B), polymer (A) comprising at least about 88.4 weightpercent of units derived from propylene and about 5.8 to about 11.6weight percent of units derived from ethylene, and is characterized ashaving a DSC curve with a T_(me) that remains essentially the same and aT_(max) that shifts to the left as the amount of comonomer in thecopolymer is increased; and polymer (B) comprising a thermoplasticpolymer other than polymer (A).
 33. The blend of claim 32 in whichpolymer (A) is further characterized as having an X-ray diffractionpattern exhibiting more gamma-form crystals than a comparable copolymerprepared with a Ziegler-Natta catalyst.
 34. The blend of claim 32 inwhich the polymer (A) is characterized further as having at least one ofthe following additional properties: (i) a B-value of about 1.4 when thecomonomer content of the copolymer is about 5.8 weight percent, and (ii)a skewness index, Six, of about 0.32.
 35. The blend of claim 33 in whichthe polymer (A) is characterized further as having at least one of thefollowing additional properties: (i) a B-value of about 1.4 when thecomonomer content of the copolymer is about 5.8 weight percent, and (ii)a skewness index, S_(ix), of about −0.32.
 36. The blend of claim 34 inwhich the polymer (A) is characterized further as having both of theproperties of (i)-(ii).
 37. The blend of claim 35 in which the polymer(A) is characterized further as having both of the properties of(i)-(ii).
 36. The blend of claim 32 in which polymer (B) is apolyolefin.
 39. The blend of claim 33 in which polymer (B) is apolyolefin.
 40. The blend of claim 34 in which polymer (B) is apolyolefin.
 41. The blend of claim 35 in which polymer (B) is apolyolefin.
 42. The blend of claim 36 in which polymer (B) is apolyolefin.
 43. The blend of claim 37 in which polymer (B) is apolyolefin.